Field
This application relates to audio headphones, specifically an improved mechanism for stereo headphones.
Prior Art
As many audiophiles and laypeople are aware, most contemporary commercial audio recordings are split into two stereo channels, generally designated as “Left” and “Right”; this is true of radio and television broadcasts, video games, and recorded music or sound on all modern media. Traditional headphones, which have two earpieces, separate these two channels by sending one to each ear. The listener perceives these two signals as an integrated whole, but is also able to recognize that the sound from the right channel may differ from that of the left; while the content of two channels may be identical, it is common for the musician, producer, or engineer to place certain instruments/vocals/etc. at different volumes in the two channels, to place them in one channel but not the other, or to “pan” them back and forth between the left and right channels, creating the effect of “sound movement” for the listener.
Thus, stereo separation is an important aspect of the recording of audio, for both aesthetic and functional purposes; the ability of the listener to hear and distinguish between the two stereo channels is a key aspect of the listening experience, whether for the full enjoyment of a musical recording or to recognize the direction of approach of an enemy in a computer game.
Each year, 60,000 individuals in the U.S. are diagnosed with unilateral (i.e., single-ear) deafness or hearing loss. Many of these individuals regularly use headphones to listen to music or other sound recordings, play games, and watch video; unlike the general population, however, most of these listeners are missing half of the “sonic picture.” They generally use conventional headphones, and thus can only hear the single audio channel that is going into their functional ear; they are likely to miss some of the effects afforded by the relative positioning and “motion” of sound between the two channels, and (if any portions of the music are solely in the channel of their impaired ear) might even be completely unable to hear certain instruments or vocals.
Several options are available for people with unilateral hearing loss who wish to experience both halves of their audio recordings through headphones. Monaural (one-channel) headsets/earpieces do exist, but these simply remove one of the two stereo channels altogether rather than combining them into one earpiece, so the listener is no better off than with stereo headphones. Using a stereo-to-mono adapter with mono headphones does achieve the desired effect, but these adapters can make portable devices awkward to carry, as they are prone to breaking, which can damage the audio output of the device. Furthermore, combining the stereo channels in this manner can short-circuit the audio device and cause damage. Additionally, since both channels are perceived through a single sound source, listeners using this method are unable to appreciate the channel separation, stereo width, and side-to-side panning that are a crucial part of the stereo experience. Finally, the transmission of dual audio signals through a single earphone source can lead to less-than-optimal sound quality, because the two signals can interfere with each other, boosting some frequencies of the audio signal and canceling out others.
Lately, it has become possible to purchase headphones/earbuds that combine both stereo channels into a single earpiece, allowing listeners to plug straight into their devices without the use of the aforementioned stereo-to-mono adapter. This type of headphone is currently the best solution available to listeners with unilateral hearing loss, but it is not without its problems. These headphones are usually custom-made by boutique brands, with premium price tags to match. As they utilize a single speaker, they are subject to the same weaknesses as the mono headphones and adapter: a lack of stereo separation and the likelihood of signal interference. Additionally, many listeners with unilateral hearing loss like to have an earpiece covering both ears while using headphones in public, to avoid someone attempting to speak into their deaf ear; single stereo earbuds leave the impaired ear exposed, so some individuals instead opt for the less ideal traditional headphones or earbuds to avoid awkward social moments.
“Surround sound” headphones have multiple sound sources in each earpiece which are designed to simulate the “front” and “rear” channels of a surround sound-enabled movies and games, but the “left” and “right” stereo channels still go to the corresponding ear in these products, leaving unilaterally deaf users still missing half of the action.